I have no clue about WebMoney, but ...

On the merchant side of things, pretty much everything is better than credit cards - as the latter gives both a chargeback risk (we had ~1% loss on chargebacks, plus lots of costs avoiding chargebacks in the first place back when I worked for an online gambling company) and hefty fees (often sth like 2.5%).

On the customers side of things, pretty much everything is better than to punch in an 11 digit credit card number plus full name, CCV-code and expiry date.

Now, what can Webmoney offer, compared to integrating directly with a bitcoin node? Well, I suppose it's mostly administration and legal matters ... for a "traditional" company that aren't already in the crypto space, getting fiat to the bank account fits well into the accounting system. Receiving bitcoins ... technically easy, but difficult from the accounting perspective.